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tiene @anni CHARLES R. TIS AND NORTON P. TIS, OF YONKL'ERS, NEW YORK.

Letters Patent No. 83,7 25, dated November 3, 1868 IIVIPROVEMENT 1NHOISTING-APPARATUS.

The Schedule referred to in these Letters Patent und making part of thesame.

To all icltom, tt may concern:

Be it known that we, (inmunes R. O 'rrs and Non- 'rON l?.` Oris, both ofYorkers, in the county of West -end elevations'of a hoisting-apparatusconstructed according to our improvement, and g Y Figure 3 represents apartly sectionalrear elevation Y or view, at right angles to iig 1. ofthe same.

Similar letters of referance indicate corresponding parts throughout theseveral iigures,

The leading feature or object of our invention is the running ofhoisting-apparatus at what may be termed rapid velocity', withoutobiectionable noise-an important consideration where the same isdesigned for hotel -use and other purp0ses. To accomplish this, weemploy endless screws, working-in worm-wheels at opposite ends or sidesof the drum, to divide or equalize wear; and the nature of our inventionconsists in coupling said screws or their shafts togetl1er,by means ofstrap or belt, and Connecting the worin-wheels, which they serve todrive, with the hoisthig-drum, through interposed ratchet orspring-attachments, or both, wherehythe workis divided between the twoscrews,

thus reducing strain and wear, and which, owing to the almostunavoidable slipping of the beit, and other causes, itis impraoticableto attain otherwise.

Referring to the accompanying drawing, Areprcsents the' hoisting-drum,which is here supposed to be y fast to its shaft, a, that issupportedand works in suit.

able bearings, l1. B is the hoisting-rope or chain, and

C the pulley over which the same is passed, to connect with the platform'of the apparatus.

To illustrate the dierent means that may be einployed, either separatelyor concerted, in carrying out our improvement, the drum A is shown asdriven at one end, through the interposition of springs, S, and atlitsother end through a ratchet-wheel, R, and pawl or pawls, the action ofwhich devices is hereinafter de-V scribed; but so far, as the principleof operation is conce1-ned, a spuug-attachment may be substituted forthe ratchet, or a ratcheteattachment for the spring.

D D' are driving-pulleys, set in motion by any suit# able means, andcoupled by belt or strap, G, that may be kept taut by atightening-pulley, H. The pulleys l) Doarry on their shafts c c' endlessscrews E l", ananged to gear with' and drive worm-wheels llA F', which,by means of sleeves or otherwise, are loosely v hung on the drum-shafta. The ratchet-wheel R -is connected with the one worm-wheel F, andgears with fthe drum by or through a spring-borne pawi or pawls,

d, while the other worm-wheel, F', is connected with the drum throughthesprings S, carried by said wheel acting on or in connection withstuds e, projecting from or made fast to the drum.

f From this description it will be perceived that screws being employedas drivers, and belt and pulleys being used in the place of spur-gear tooperate them, a comparatively noiseless action is secured, but, as themotion derivable from screws is naturally slow, it becomes necessary, inorder to give the requisite speed to the hoisting-drum, that the pulleyswhich operate the screwsshould be rotated at a very high Velocity, inaccomplishing which the belt that couples said pulleysis apt,occasionally, to slip on one or other of the latter,

by reason of adierence inthe smoothness or biting-y condition. oi theirperipheries, or from other causes. This has the eect of throwing all thework upon the screws, but by themeans we interpose to connect the.worm-wheels with the drum, such eiect is neutralized', and the workdivided between the two screws, so as to reduce strain and wear. Thus,by the application of the springs S and ratchet-wheel R, for instance,supposing, in hoisting, the wheel F to run the fastest, then theratchet-wheel R takes the lead in driving, causing increased compressionof the springs S, which .resist-ance is felt or transferred through thewheel F to the' screw E, that operates the latter, and thus the strainor wear is divided between the two screws, while,

ii' the wheel F run the fastest, the springs S take the lead in driving,and are extended, causing the ratchetwheel R to slip the pawl or pawlsd, till the action of the springs causesa division of the strain. It maybe preferred to dispense withthe ratchet-attachment, and employ ,springsat both ends, or no springs, and ratchets at both ends of the drum, inwhich latter case, and by a suitable disposition of the pawls,theworm-wheel that actsvas a' driver in hoisting 'will lag in lowering,and thus the wear upon the screws be divided, the one bearing the strainin hoisting, and the other in the reverse motion of the drum. It ispreferable, to secure a sensitive adjustment of the interposeddriving-at tachments, that either one of the pulleys D D should beslightly of larger diameter than the other.

What is here claimed as new, and desired to he secured byLetters Patent,is-

The combination, with the hoisting-drum, of screws `operated throughpulleys, by a belt or band coupling ments, or either, substantially asspecified.

CEAS; R. OTIS. NORTON P. OTIS.

YVitnesses:

M. M. VAIL, `Minor Winslow.

